property at 647 Fifth Avenue, were all acquired in May 1950 by the Phoenix Mutual Life Insurance Company. The buyer, who reportedly paid for the buildings in cash, held the properties as an investment and continued leasing 653 Fifth Avenue to Cartier. In the late 1950s, design firm Design-Technics had a showroom at 4 East 52nd Street, though the firm moved out after 1959, when it leased another building on 53rd Street. 1960s to 1980s The New York City Landmarks Preservation Commission (LPC) designated the Cartier Building as a city landmark on February 5, 1967. Cartier officials threw a party at the Plaza Hotel to celebrate the designation. In designating the building as a landmark, the LPC assumed Cartier owned the building. Phoenix had never even been aware of the landmark status, let alone attended any hearing about it. Once Phoenix learned of the action, it asked the LPC to reconsider the landmark designation, as such a status prohibited major alterations to a building's facade without the LPC's permission. As a result, the landmark status was revoked in August 1967. LPC rules at the time prevented the agency from reconsidering the building as a landmark until 1970. The Cartier Building was re-designated as a city landmark on July 14, 1970. In the late 1960s, Best & Co. purchased the development rights over the Cartier Building. This permitted Best's to erect a skyscraper above their store, which was two buildings south of Cartier's. Aristotle Onassis—the president of Olympic Airways, which at the time had a sales office at 647 Fifth Avenue—established a family trust called Victory Development in March 1970. Victory formed a joint venture with Arlen Realty & Development Corporation to acquire Best's store, 647 Fifth Avenue, and the Cartier Building. The Best & Co. store closed in late 1970 and it was demolished the next year to make way for the Olympic Tower. As part of the Olympic Tower's construction, a pedestrian plaza was built east of 647 Fifth Avenue and the Cartier Building. The tower was ultimately completed and dedicated in 1974. A Ben Kahn fur salon opened at 4 East 52nd Street in November 1970; at the time, Ben Kahn and Cartier were both owned by the Kenton Corporation. Kenton sold Ben Kahn in 1972, and Cartier opened Les Must de Cartier, a watch boutique, inside 4 East 52nd Street in 1976. Cartier celebrated its 75th anniversary